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Developed at the University of Bristol, the batteries are designed to offer a sustainable alternative to lithium-ion batteries, which offer high performance and reusability but are associated with environmental issues related to lithium mining. The new batteries could be used as sustainable alternatives in electric cars and for large-scale renewable energy storage.
Compared to lithium, sodium and potassium batteries have historically had lower charge-discharge rates and reusability. This inferior performance was due to the larger sizes of sodium and potassium ions, which have to move through porous carbon electrodes in the batteries.
Collaborating with researchers at Imperial College, a team at the Bristol Composites Institute developed new carbon electrode materials based on an ‘ice-templating’ system. Cellulose nanocrystals are formed into a porous structure using ice crystals, which are grown and then sublimated, to form aerogels. This leaves large channels within the structure that can carry the sodium and potassium ions.
According to the team’s research paper, the sodium- and potassium-ion batteries can outperform many other comparable systems.
Corresponding author Steve Eichhorn said: “We were astounded with the performance of these new batteries. There is great potential to develop these further and to produce larger scaled devices with the technology.”
He added: “In light of these findings, we now hope to collaborate with industries to develop this strategy on an industrial scale, and to explore whether this unique technology can be easily extended to a variety of other energy storage systems such as zinc-, calcium-, aluminium- and magnesium-ion batteries, thus demonstrating its universal potential in next-generation energy storage systems.”
Sustainable sourcing of the cellulose is another attractive quality for the batteries.
Lead author Jing Wang said: “Benefiting from the renewability of the precursor and scalability at relatively low cost in the environmentally benign synthesis process, this work could offer an appealing route to promote large-scale applications of sustainable electric vehicles and large-scale energy storage grids in the near future.”
The paper was published in Advanced Functional Materials.
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